RESUMO
In this work the formation of laser-induced periodic surface structures (LIPSS) on a titanium surface upon irradiation by linearly polarized femtosecond (fs) laser pulses with a repetition rate of 1 kHz in air environment was studied experimentally. In particular, the dependence of high-spatial-frequency-LIPSS (HSFL) characteristics on various laser parameters: fluence, pulse number, wavelength (800 nm and 400 nm), pulse duration (10 fs - 550 fs), and polarization was studied in detail. In comparison with low-spatial-frequency-LIPSS (LSFL), the HSFL emerge at a much lower fluence with orientation perpendicular to the ridges of the LSFL. It was observed that these two types of LIPSS demonstrate different fluence, shot number and wavelength dependencies, which suggest their origin is different. Therefore, the HSFL formation mechanism cannot be described by the widely accepted interference model developed for describing LSFL formation.
RESUMO
Research suggests that online interventions preventing risky substance use can improve student health. There is an increasing interest in transferring evidence-based online programs into university health promotion practice. However, little is known about how to best tailor the implementation process to capacities and context of individual universities. The purpose of this study was to assess the level of readiness (capacity) of German universities concerning the implementation of evidence-based online programs for risky substance use prevention employing an adapted Community Readiness Assessment (CRA) and to develop tailored action plans for implementation. The CRA involved 43 semi-structured interviews with key persons at 10 German universities. The interviews addressed five dimensions (knowledge of efforts, leadership, community climate, knowledge of the issue, and resources) at nine possible readiness stages (no awareness-ownership) and additional contextual factors. Overall, readiness for implementing online interventions across universities was rather low. Universities readiness levels ranged between the denial stage with a score of 2.1 and the preplanning stage with a score of 4.4. University-specific readiness was very heterogeneous. On the basis of the results of the CRA, universities received feedback and options for training on how to take the necessary steps to increase readiness and to prepare program implementation. The adapted version of the CRA was well suited to inform future implementation of evidence-based online programs for the prevention of risky substance use at participating universities.
Assuntos
Transtornos Relacionados ao Uso de Substâncias , Universidades , Alemanha , Promoção da Saúde , Humanos , Estudantes , Transtornos Relacionados ao Uso de Substâncias/prevenção & controleRESUMO
We demonstrate continuous infrared spectra from 20 nm sample spots, by combining dispersive Fourier-transform infrared spectroscopy (FTIR) with scattering near-field microscopy (s-SNOM). With the "apertureless" tip of a standard AFM cantilever in one arm of a Michelson interferometer the spectra arise simultaneously in amplitude and phase. The effect of near-field phonon resonance of SiC is used to verify background-free s-SNOM operation, and to determine the absolute scattering efficiency, at 6 cm(-1) spectral resolution. We further report first evidence of free-induction decay from a scatterer composed of parts coupled by near-fields. This is possible only with broadband illumination. It offers a new, unique tool to discriminate against background scattering artifacts.
Assuntos
Interferometria/instrumentação , Microscopia de Força Atômica/instrumentação , Óptica e Fotônica , Espectrofotometria Infravermelho/métodos , Desenho de Equipamento , Análise de Fourier , Processamento de Imagem Assistida por Computador , Lasers , Reprodutibilidade dos Testes , Espalhamento de RadiaçãoRESUMO
BACKGROUND: Many intervention efforts targeting student drinking were developed to address US college students, which usually involves underage drinking. It remains unclear, if research evidence from these interventions is generalizable to university and college students of legal drinking age, e.g., in Europe. OBJECTIVE: To evaluate the effectiveness of a translated and adapted version of the eCHECKUP TO GO, applied as stand-alone web-based electronic screening and brief intervention (e-SBI), in German university students at risk for hazardous drinking. METHODS: A fully automated web-based two-arm parallel-group randomized controlled trial was conducted. Participants were randomized to an e-SBI or assessment-only (AO) condition. The current paper analyzed students with baseline AUDIT-C scores ≥3 for women and ≥4 for men (sample at baseline: e-SBI [n=514], AO [n=467]; 3-month follow-up: e-SBI [n=194], AO [n=231]; 6-month follow-up: e-SBI [n=146], AO [n=200]). The primary outcome was prior four weeks' alcohol consumption. Secondary outcomes were frequency of heavy drinking occasions, peak blood alcohol concentration, and number of alcohol-related problems. RESULTS: Mixed linear model analyses revealed significant interaction effects between groups and time points on the primary outcome after 3 and 6months. Compared to students in the AO condition, students in the e-SBI condition reported consuming 4.11 fewer standard drinks during the previous four weeks after 3months, and 4.78 fewer standard drinks after 6months. Mixed results were found on secondary outcomes. CONCLUSIONS: The results indicate that evidence on and knowledge of web-based e-SBIs based on US college student samples is transferable to German university students of legal drinking age. However, knowledge of what motivates students to complete programs under voluntary conditions, although rare, is needed.
Assuntos
Consumo de Álcool na Faculdade/psicologia , Transtornos Relacionados ao Uso de Álcool/psicologia , Transtornos Relacionados ao Uso de Álcool/terapia , Internet , Psicoterapia Breve/métodos , Estudantes/psicologia , Adolescente , Adulto , Concentração Alcoólica no Sangue , Feminino , Alemanha , Humanos , Masculino , Pessoa de Meia-Idade , Estudantes/estatística & dados numéricos , Resultado do Tratamento , Universidades , Adulto JovemRESUMO
Recent research revealed that action video game players outperform non-players in a wide range of attentional, perceptual and cognitive tasks. Here we tested if expertise in action video games is related to differences regarding the potential of shortly presented stimuli to bias behavior. In a response priming paradigm, participants classified four animal pictures functioning as targets as being smaller or larger than a reference frame. Before each target, one of the same four animal pictures was presented as a masked prime to influence participants' responses in a congruent or incongruent way. Masked primes induced congruence effects, that is, faster responses for congruent compared to incongruent conditions, indicating processing of hardly visible primes. Results also suggested that action video game players showed a larger congruence effect than non-players for 20 ms primes, whereas there was no group difference for 60 ms primes. In addition, there was a tendency for action video game players to detect masked primes for some prime durations better than non-players. Thus, action video game expertise may be accompanied by faster and more efficient processing of shortly presented visual stimuli.